Density-functional investigation of the rhombohedral to simple cubic phase transition of arsenic

We report on our investigation of the crystal structure of arsenic under compression, focusing primarily on the pressure-induced A7 to simple cubic (sc) phase transition. The two-atom rhombohedral unit cell is subjected to pressures ranging from 0 GPa to 200 GPa; for each given pressure, cell lengths and angles, as well as atomic positions, are allowed to vary until the fully relaxed structure is obtained. We find that the nearest and next-nearest neighbor distances give the clearest indication of the occurrence of a structural phase transition. Calculations are performed using the local density approximation (LDA) and the PBE and PW91 generalized gradient approximations (GGA-PBE and GGA-PW91) for the exchange-correlation functional. The A7 to sc transition is found to occur at 21+/-1 GPa in the LDA, at 28+/-1 GPa in the GGA-PBE and at 29+/-1 GPa in the GGA-PW91; no volume discontinuity is observed across the transition in any of the three cases. We use k-point grids as dense as 66X66X66 to enable us to present reliably converged results for the A7 to sc transition of arsenic.Comment: To be published in Physical Review B; material supplementary to this article is available at arXiv:0810.169

Parental experiences of the impacts of Covid-19 on the care of young children; qualitative interview findings from the Nairobi Early Childcare in Slums (NECS) project

Introduction: The Covid-19 pandemic, and societal attempts to control it, have touched almost every aspect of people’s lives around the world, albeit in unequal ways. In particular, there is considerable concern about the way that stringent ‘lockdowns’, as implemented in Kenya and many other countries, affected young children, especially those living in informal settlements. However, to date, there has been little research attempting to unpack and understand how the pandemic has impacted on the care of young children. // Methods: In-depth telephone interviews were conducted with 21 parents/carers of children aged under five years living in three Nairobi slums between May and September 2021 exploring the ways in which Covid-19, and policies to control the pandemic, impacted on their household and the care of their child/children. // Results: The impacts of Covid-19 control measures on the care of children have been widely felt, deep and multiple. The impact of economic hardship has been significant, reportedly undermining food security and access to services including healthcare and childcare. Respondents reported an associated increase in domestic and community violence. Many people relied on help from others; this was most commonly reported to be in the form of variable levels of flexibility from landlords and help from other community members. No direct harms from Covid-19 disease were reported by respondents. // Conclusion: The impacts of Covid-19 control measures on the care of young children in informal settlements have been indirect but dramatic. Given the breadth and depth of these reported impacts, and the particular vulnerability of young children, deeper consideration ought to inform decisions about approaches to implementation of stringent disease control measures in future. In addition, these findings imply a need for both short- and long-term policy responses to ameliorate the impacts described

Parental experiences of childcare in an informal urban settlement: qualitative interview findings from the Nairobi Early Childcare in Slums (NECS) project

OBJECTIVES: To gain an in-depth understanding of parent/carers' perspectives on, and decision-making about, early childhood care in general, and paid childcare specifically, in informal settlements in Nairobi. DESIGN: In-depth telephone interviews, conducted using a topic guide, were analysed through a combination of deductive and inductive thematic analysis and regular reflexivity meetings. We explored parents' childcare needs and experiences over time, and their perspectives on the provision of paid childcare in the slums. SETTING: Three informal settlements or slums in Nairobi: Kibera; Kawangware; and Mukuru-Viwandani. PARTICIPANTS: A purposively selected sample of 21 parental and non-parental carers of children aged under 5 years who were currently living in three Nairobi slums, including men and women, and users and non-users of paid childcare. RESULTS: Childcare is complex, with a plurality of approaches being used. Common strategies include family member provided care (often but not exclusively by mothers, at home or at a place of work), paid childcare and informal or ad hoc arrangements with neighbours. Childcare decision-making in these settings is constrained by economics and the broader context of living in the slum. Paid childcare is frequently used, but is widely understood to be lacking in quality, especially for the poorest. Quality of childcare is understood to comprise a combination of structural factors, such as the physical space, play and learning resources and processes such as interactions between the care provider and children or parents. CONCLUSIONS: These findings suggest a need, and opportunity, to improve early childhood care in slums. Understanding parental perspectives on both the deficiencies and valued features of childcare is likely to be vital to informing efforts to improve childcare in these settings

EFECTO ENERO EN ACCIONES Y ADRS DE LAS EMPRESAS BRASILEÑAS DESPUÉS DEL INICIO DE TRIBUTACIÓN DE LA GANANCIA SOBRE EL CAPITAL EN BRASIL

Os retornos anormais para preços de ações observados no mês de janeiro (“efeito janeiro”) são uma evidência consistente da previsibilidade dos retornos, observada em diversos mercados financeiros ao redor do mundo, tendo como principal explicação a realização de perdas para reduzir o pagamento de impostos. Entretanto, as evidências até aqui relatadas para o mercado brasileiro conflitam com os fatos estilizados de outros mercados. Dessa forma, o presente trabalho tem por objetivo avaliar a existência do “efeito janeiro” em uma análise transversal dos retornos mensais de ações de empresas brasileiras, no período de 1996 a 2013, ampliando a metodologia de análise em diferentes subamostras. Trabalhos anteriores que estudaram esse efeito no mercado brasileiro tomaram períodos anteriores a 1996, quando não havia tributação sobre ganhos de capital no Brasil. Além disso, filtraram ações de menor valor de mercado, ou analisaram apenas índices agregados, como o IBOVESPA, quando o “efeito janeiro” seria mais acentuado em empresas de menor valor de mercado. Na análise aqui relatada, o “efeito janeiro” foi identificado, e com maior intensidade quando o retorno negativo em dezembro era maior, consistentemente com a hipótese de gestão tributária dos ganhos de capital. Não foi identificada evidência do “efeito janeiro” na subamostra de empresas que negociam ADRs na NYSE, empresas de maior valor de mercado, em geral.The abnormal returns for stock prices observed in January (known as the "January effect") are evidence of the predictability of returns. This anomaly is observed in many financial markets around the world.Its main explanation is the booking of capital losses in an effort to reduce taxes payment. Thus, this study aims to assess the existence of the "January effect" in a cross-sectional analysis of monthly returns of shares of Brazilian companies in the period between 1996–2013 (both included. Previous studies which have investigated this effect in the Brazilian market took periods prior to 1996, when there was no capital gains tax in Brazil.  In the applied methodology, the econometric model controls for other anomalies (momentum effect and short term reversion), which also influence the autocorrelation of returns, and can not, therefore, be omitted. In the analysis reported here, the "January effect" was identified, and with greater intensity when the negative return in December was greater, consistent with the hypothesis of tax management of capital gains. No evidence was identified in the "January effect" in the subsample of firms that trade ADRs on the NYSE, composed of companies with higher market value, and more influenced by foreigner investors.Los retornos anormales para precios de acciones observadas en el mes de enero (“efecto enero”) son una evidencia de la previsibilidad de los retornos. Esa anomalia es observada en distintos mercados financieros alrededor del mundo, teniendo como principal explicación, la realización de pérdidas para reducir los pagos de impuestos. El presente trabajo tiene como objetivo evaluar la existencia del “efecto enero” en un análisis transversal de los retornos mensuales de acciones de empresas brasileñas, en el período entre 1996 y 2013. Trabajos previos que estudiaron ese efecto en el mercado brasileño comprenden los períodos anteriores a 1996, cuando todavía no había tributación de ganancia sobre el capital en Brasil. En la metodología empleada, el modelo econométrico controla por los efectos de otras anomalías (efecto momentum y inversión de corto plazo) que también influyen en la autocorrelación de los rendimientos y, por tanto, no se pueden omitir. En el análisis aquí señalado, el “efecto enero” fue  identificado, y con mayor magnitud cuando el retorno negativo en diciembre era mayor, consistentemente con la hipótesis de gestión tributaria de las ganancias de capital. No fue identificada evidencia del “efecto enero” en la submuestra de empresas que negocian ADRs en la NYSE, compuesta por empresas con mayor valor de mercado y más sujetas a la influencia de los inversores internacionales

Association of skeletal muscle and serum metabolites with maximum power output gains in response to continuous endurance or high-intensity interval training programs: The TIMES study - A randomized controlled trial

Recent studies have begun to identify the molecular determinants of inter-individual variability of cardiorespiratory fitness (CRF) in response to exercise training programs. However, we still have an incomplete picture of the molecular mechanisms underlying trainability in response to exercise training. Objective We investigated baseline serum and skeletal muscle metabolomics profile and its associations with maximal power output (MPO) gains in response to 8-week of continuous endurance training (ET) and high-intensity interval training (HIIT) programs matched for total units of exercise performed (the TIMES study). Methods Eighty healthy sedentary young adult males were randomized to one of three groups and 70 were defined as completers (> 90% of sessions): ET (n = 30), HIIT (n = 30) and control (CO, n = 10). For the CO, participants were asked to not exercise for 8 weeks. Serum and skeletal muscle samples were analyzed by 1H-NMR spectroscopy. The targeted screens yielded 43 serum and 70 muscle reproducible metabolites (intraclass > 0.75; coefficient of variation < 25%). Associations of baseline metabolites with MPO trainability were explored within each training program via three analytical strategies: (1) correlations with gains in MPO; (2) differences between high and low responders to ET and HIIT; and (3) metabolites contributions to the most significant pathways related to gains in MPO. The significance level was set at P < 0.01 or false discovery rate of 0.1. Results The exercise programs generated similar gains in MPO (ET = 21.4 +/- 8.0%; HIIT = 24.3 +/- 8.5%). MPO associated baseline metabolites supported by all three levels of evidence were: serum glycerol, muscle alanine, proline, threonine, creatinine, AMP and pyruvate for ET, and serum lysine, phenylalanine, creatine, and muscle glycolate for HIIT. The most common pathways suggested by the metabolite profiles were aminoacyl-tRNA biosynthesis, and carbohydrate and amino acid metabolism. Conclusion We suggest that MPO gains in both programs are potentially associated with metabolites indicative of baseline amino acid and translation processes with additional evidence for carbohydrate metabolism in ET142CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP149201/2015-0; 140302/2018-288881.135219/2016-012018/24108-9; 2016/057417Sao Paulo Research Foundation (FAPESP)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [2018/24108-9, 2016/057417]; Support Fund for Teaching, Research and Extension (FAEPEX) [2021/16]; National Council for Scientific and Technological Development (CNPq)National Council for Scientific and Technological Development (CNPq) [149201/2015-0, 140302/2018-2]; Coordination for the Improvement of Higher Education Personnel (PDSE-CAPES) [88881.135219/2016-01]; COBRE center grant from the U.S.A. National Institutes of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [NIH8 1P30GM118430-02]; NIH-funded COBRE grantUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USA [NIH 8P30GM118430-01]; National Institute of General Medical Sciences of the National Institutes of HealthUnited States Department of Health & Human ServicesNational Institutes of Health (NIH) - USANIH National Institute of General Medical Sciences (NIGMS) [2 U54 GM104940

The Role of Plant Latex in Virus Biology

At least 20,000 plant species produce latex, a capacity that appears to have evolved independently on numerous occasions. With a few exceptions, latex is stored under pressure in specialized cells known as laticifers and is exuded upon injury, leading to the assumption that it has a role in securing the plant after mechanical injury. In addition, a defensive effect against insect herbivores and fungal infections has been well established. Latex also appears to have effects on viruses, and laticifers are a hostile environment for virus colonization. Only one example of successful colonization has been reported: papaya meleira virus (PMeV) and papaya meleira virus 2 (PMeV2) in Carica papaya. In this review, a summary of studies that support both the pro- and anti-viral effects of plant latex compounds is provided. The latex components represent a promising natural source for the discovery of new pro- and anti-viral molecules in the fields of agriculture and medicine

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio